package com.hmdp.utils;

import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

/**
 * @author Administrator
 */
@Component
public class RedisIdWorker {
    //redis实现全局唯一id  符号位0   时间戳 （31bit）      序列号（32bit）

    //开始时间戳
    private static final long BEGIN_TIMESTAMP = 1640995200L;

    private StringRedisTemplate stringRedisTemplate;

    public RedisIdWorker(StringRedisTemplate stringRedisTemplate) {
        this.stringRedisTemplate = stringRedisTemplate;
    }

    //序列号的位数
    private static final int COUNT_BITS = 32;

    public long nextId(String keyPrefix) {

        //生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timestamp = nowSecond - BEGIN_TIMESTAMP;
        //生成序列号,先获取当前日期
        String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        //日期key自增长 //不用担心空指针，因为新的一天他会自动加一
        long count = stringRedisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + date);
        //拼接返回

//        return timestamp<<32; //采用或运算，一真则真
        return timestamp << COUNT_BITS | count;
    }

    public static void main(String[] args) {
        LocalDateTime time = LocalDateTime.of(2022, 1, 1, 0, 0, 0);
        long epochSecond = time.toEpochSecond(ZoneOffset.UTC);
        System.out.println(epochSecond);
    }
}
